五自由度次镜调整机构的研究

Research of five-degree-of-freedom adjustment mechanismfor secondary mirror

在同轴望远镜系统中,主镜和次镜的相对位置和姿态有非常严格的要求,需要将次镜设计成多自由度可以调整的机构.针对次镜调整机构的性能要求,提出一套由二维XY移动平台和三维Tip/Tilt/Focus平台组合成的五自由度次镜调整机构方案.其中三维Tip/Tilt/Focus平台由3个驱动器、定平台与动平台组成,驱动器与动平台之间由柔性铰链连接,通过3个驱动器的伸缩和柔性铰链的转动来实现动平台的三自由度运动.对三维Tip/Tilt/Focus平台的运动学原理作了详细介绍,深入地讨论柔性铰链弯曲刚度和轴向刚度与几何参数的关系.研究结果为五维调整机构及柔性铰链的设计提供客观依据,具有较大的实际意义.

In the coaxial telescope system,the relative position and pose between primary mirror and secondary mirror are strictly required.Therefore,a multi-degree-of-freedom adjustment mechanism for secondary mirror is needed.To satisfy the specifications of the adjustment mechanism for secondary mirror,a device consisted of a XY translation stage and a Tip/Tilt/Focus stage was presented.The Tip/Tilt/Focus stage was composed of three actuators,fixing and moving platform which were connected by flexure hinges.The motion of the platform was performed by the extension of three actuators and the rotation of flexure hinges.The kinematic principles of Tip/Tilt/Focus platform were introduced with details,then the flexure hinges were considered,and the relationship between geometric parameters of flexure hinges and bending axial rigidity was detailed.This paper provides an objective basis on design of five-degree-of-freedom adjustment mechanism and flexure hinges,which could be applied in precision engineering.